Fuel systems and oxidizers

ABSTRACT

7. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising a liquid composition consisting essentially of from about 59 percent to about 77 percent by weight of perchloric acid, from 0 to about 15 percent by weight of HNO3 and the remainder water, the amount of water being sufficient to form dihydrated perchloric acid with at least about 95 percent of the perchloric acid and a fuel selected from the group consisting of light metals, metal hydrides, and mixtures thereof.

United States Patent Greiner et a1.

[ 1 Dec. 12, 1972 [54] FUEL SYSTEMS AND OXIDIZERS [73] Assignee: TexacoExperiment Incorporated,

Richmond, Va.

[22] Filed: Jan. 21, 1963 [21] Appl. No.: 253,523

[52] US. Cl. ..60/2l4, /215, 60/216, 60/219, 149/74, 149/109 [51] Int.Cl. ..C06d 5/08, C06d 5/10 [58] Field of Search ..60/35.4, 214-216,60/219; 149/74, 75, 109', 23/152 [56] References Cited UNITED STATESPATENTS 3,083,526 4/1963 Hudson ..60/35.4

2,504,119 4/1950 Frazer et al. 149/75 2,968,539 1/1961 Wharton 149/752,975,045 3/1961 Perry et a1 ..149/

Primary Examiner-Benjamin R. Padgett Attorney-Stowe" & Stowell EXEMPLARYCLAIM 7. A method of producing thrust which comprises reacting in acombustion chamber an oxidizer comprising a liquid compositionconsisting essentially of from about 59 percent to about 77 percent byweight of perchloric acid, from 0 to about 15 percent by weight of HNO,and the remainder water, the amount of water being sufficient to formdihydrated perchloric acid with at least about percent of the perchloricacid and a fuel selected from the group consisting of light metals,metal hydrides, and mixtures thereof.

13 Claims, No Drawings FUEL SYSTEMS AND OXIDIZERS This invention relatesto improvements in fuel systems and fuel oxidizers for reaction motors.

It is an object of the present invention to provide fuel oxidizers andfuel systems which have good performance and are relatively safe tohandle in that they do not product toxic fumes, are very stable, and arerelatively non-injurious to skin.

A further object is to provide fuel systems and fuel oxidizers whichhave good specific impulse and good density impulse and wherein theliquid component of the fuel system has a relatively high boiling pointand a relatively low freezing point.

A further object is to provide a liquid-solid hybrid propellant systemhaving particular utility and performance on boost-type missions butwhich may also be used for second-stage and sustainer missions. Thepropellant systems of the invention are of special utility involume-limited rockets where the fuel density-impulse relationship isimportant.

These and other objects and advantages are provided in a liquid-solidpropellant system comprising as an oxidizer dihydrated perchloric acid,and a fuel consisting predominantly of a light metal or a metal hydrideand by an improved oxidizer for a light metal or a metal hydridecomprising at least about 80 percent by weight of dihydrated perchloricacid.

It has been found that hybrid rocket propellants consisting of at leastabout 80 percent by weight of dihydrated perchloric acid as oxidizer anda fuel consisting predominantly of a light metal or a metal hydrideprovide very high performance on an integrated specific impulse anddensity basis, high safety, long storability and the capability ofoperation with the thrust of the reaction motor controlled over a widethrust range by controlling the flow of liquid oxidizer to the fuelcomponent of the hybrid system.

The following selected hybrid systems have been found to provide verysatisfactory results:

Table I shows calculated performance data including the specific impulsefor two illustrative rations of reactants in the propellant system ZrHHClO 21-1 0.

Thermodynamic Characteristics: Chamber Exhaust Chamber ExhaustTemperature, K 4212.0 2961.1 3353.8 2425.8 Moles of Gas,

moles/g 1.683 1.5475 1.5366 1.5128 Combustion Products. moles/100gGaseous Atoms 11 0.3630 0.1884 0.0696 0.0247 0 0.0008 0.0000 0.00000.0000 Cl 0.0397 0.0231 0.0000 0.0000 Zr 0.0001 0.0000 0.1276 0.1281Gaseous Molecules H 1.0298 1.1159 1.2335 1.2563 H1O 0.0179 0.0056 0.00000.0000 0H 0.0040 0.0003 0.0000 0.0000 HCl 0.1804 0.2112 0.0009 0.0000ZrO 0.0026 0.0000 0.0108 0.0089 ZrCl: 0.0099 0.0030 0.0942 0.0947 Liquidand Solid Molecules ZrO;(1) 0.7080 0.7178 0.5627 0.0000 ZrO,(s) 0.00000.0000 0.0000 0.5636

Table 11 shows calculated performance data including the specificimpulse for an illustrative ratio of reactants in the propellant systemZrH NH CIO HClO 211 0 HNO H 0.

TABLE 11 Ingredients: moles gl 1 00g ZrH, 1.0189 72.092 Nl-1 Cl0 0.042553.794 HC10 21-1,) 0.26930 20.310 HNO; 0.05302 2.536 H2O 0.09274 1.268Computed Density g/cc 3.156 Performance: Shifting 1 sec 193 ShiftingVolumetric 1., lb-sec/in. 25.5 Thermodynamic Characteristics: ChamberExhaust Temperature, "K 4718 3 3 37 Moles of Gas, moles/100g 1.71281.6906 Combustion Products, moles/ 100g Gaseous Atoms H 0.2128 0.17 27Cl 0.0191 0.0187 0 0.0005 0.0001 Gaseous Molecules l-lCl 0.1632 0.1930Hg 1.2001 1.2322 ZrCl; 0.0270 0.0125 H1O 0.0491 0.0240 OH 0.0046 0.0009N, 0.0363 0.0363 Liquid and Solid Molecules ZrO,( 1) 0.7463 0.0000Zr0,(s) 0.0000 0.7608

Table 111 shows calculated performance data for an illustrative ratio ofreactants in the propellant system Zr N2H5N3 2H20.

Temperature, K 3579 Moles of Gas, moles/100g 3.9223 Combustion Products,moles/100g Gaseous Atoms H 0.1731 Cl .0.01 18 Gaseous Molecules H,1.4122 HCl 0.1452 N, 1.1800 Condensed Phases ZrO, 0.4720

Table IV shows calculated performance data for three illustrative ratiosof reactants in the propellant System N2H5N3 TABLE IV lngredients: molesg/lOOg moles g/lg moles g/100g Al 1 19.615 1 15.842 1 11.310 N H N 154.584 1 44.085 1 31.472 HClO '2H O 0.26 25.801 0.5 40.073 1 57.218Computed Density, lb/in. 0.05874 0.05930 0.05999 Computed Density. g/cc1.6258 1.6413 1.6604 Performance: Frozen 1 sec 273.1 266.1 249.4Thermodynamic Characteristics: Chamber Chamber Chamber Temperature, K3312 3391 3260 Moles ol'Gas, moles/100g 4.2981 3.9172 3.5343 CombustionProducts, moles/100g Gaseous Atoms A1 0.0099 0.0002 0.0000 C1 0.00800.0187 0.0437 0 0.0001 0.0024 0.0126 H 0.1357 0.1181 0.0329 GaseousMolecules 0, 0.0000 0 0006 0.0402 N, 1.8175 1.4679 1.0480 A1 0 0.01160.0001 0.0000 A10 0.0009 0.0003 0.0000 OH 0.0034 0.0574 0.1794 H 2.05151.1565 0.1883 HCI 0.1810 0.2748 0.3751 H1O 0.0785 0.8202 1.6139Condensed Phases A1 0 0.3465 0.2933 0.2096

moles g/lOOg Computed Density, lb/in. Computed Density, g/ccPerformance:

Frozen 1 sec Thermodynamic Characteristics:

Chamber Temperature. "K 3721 Moles of Gas,

moles/ 100g Combustion Products, moles/ 100g Gaseous Atoms H 0.2635Gaseous Molecules A1,0 0.0379 A10 0.0062 OH 0.0186 H, 1.5797 HCl 0.2594H=O 0.1395 N1 0.9879 Condensed Phases Table VI shows calculatedperformance data for an illustrative ratio of reactants in thepropellant system Zrl-l LiClO HC1O 21-1 0.

TABLE VI Ingredients: moles g/lOOg ZrH; 1 66.557 LiCIO 0.08763 6.656HC1O 2H,O 0.2749 26.787 Computed Density, lb/in. 0.1 193 ComputedDensity, g/cc 3.3015 Performance: Shifting 1 sec 190 Shifting Volumetric1 lb-sec/in. 22.667 Frozen 1 sec 190 Thermodynamic Characteristics:Chamber Exhaust Temperature, "K 4073 2960 Moles of Gas, mole/g 1.52281.4715 Combustion Products, moles/100g Gaseous Atoms H 0.2653 0.1714 Li0.0093 0.0190 C1 0.0293 0.0207 Gaseous Molecules 2 0.9675 1.0140 HCl0.1346 0.1779 LiCl 0.0533 0.0435 ZrCl1 0.0208 0.0083 H O 0.033] 0.0152OH 0.0078 0.0013 ZrO; 0.0008 0.0000 Condensed Phases ZrO2( 1) 0.69210.4945 ZrO (c) 0.0000 0.21 10 Dihydrated perchloric acid is anintrinsically stable, only slightly toxic and caustic, oxidizercontaining 73.6 percent perchloric acid and 26.4 percent water. Theoxidizer is a water-white liquid with a density of 1.713 g/cc at 25 C,boiling at about 200 C and freezing at 20 C. The dihydrated acid is noteven slightly caustic when cold which makes it safe for personnel and itdoes not require special equipment for handling.

When a lower freezing point is required for the liquid oxidizer waterand/or nitric acid may be added. Both water and/or nitric acid lower thefreezing point of the perchloric acid dihydrate. Water, however, lowersboth the density and impulse of the oxidizer while nitric acid alonewill lower the density. On the other hand, if high impulse is requiredand high density is of lesser importance, a higher proportion of nitricacid may be used. The addition of both water and nitric acid to theperchloric acid dihydrate makes it possible to provide oxidizercompositions having selected combinations of density, impulse andfreezing point to meet a variety of requirements. The nitric acidcontent may be as high as 15 percent but in general compositionscontaining not more than about 10 percent of nitric acid are preferableas they are not unduly corrosive and are safer to handle.

The liquid oxidizer compositions of the invention consist essentially offrom about 59 percent to about 77 percent by weight of perchloric acid,from 0 to about percent by weight of HNO and the remainder water, theamount of water being sufficient to form dihydrated perchloric acid withat least about 95 percent of the perchloric acid content.

The following compositions have provided very satisfactory results:

I. 93 percent dihydrated perchloric acid (DHPA), 6

percent nitric acid and 1 percent water.

2. 90 percent DHPA, 8 percent I-INO and 2 percent 3. 84.2 percentDI-IPA, 10.5 percent I-INO and 5.3

percent H O.

Table VII shows densities of I selected dihydrated perchloricacid-water-nitric acid compositions.

The improved oxidizers of the invention may be advantageously employedwith a wide variety of light metals, metal hydrides, mixtures of lightmetals and metal hydrides, and light metals and metal hydrides admixedor combined with other compatible fuels. The following list is exemplaryof suitable fuels which may be employed with the oxidizers of theinvention: Zr; Al; a; z; g; g( 4)2 3)2 3; 3)2 2 H TiH and MgI-I Of thesefuels Zr, ZrH and All-I have been found to be particularly suitable forrocket fuels with the oxidizers of the invention.

We claim:

1. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising substantially dihydrated perchloric acidand a fuel selected from the group consisting of light metals, metalhydrides and mixtures thereof.

2. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer compris ing substantially dihydrated perchloric acidand a fuel consisting predominantly of a light metal.

3. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising substantially dihydrated perchloric acidand a fuel consisting predominantly of a metal hydride.

4. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising substantially dihydrated perchloric acidand a fuel consisting predominantly of Zr.

5. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprisconsisting predominantly of AlI-I 7. A methodof pro ucmg thrust which comprises reacting in a combustion chamber anoxidizer comprising a liquid composition consisting essentially of fromabout 59 percent to about 77 percent by weight of perchloric acid, from0 to about 15 percent by weight of I-INO and the remainder water, theamount of water being sufficient to form dihydrated perchloric acid withat least about 95 percent of the perchloric acid and a fuel selectedfrom the group consisting of light metals, metal hydrides, and mixturesthereof.

8. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising about percent by weight of dihydratedperchloric acid, about 8 percent by weight of nitric acid and about 2%by weight of water and a fuel selected from the group consisting oflight metals, metal hydrides, and mixtures thereof.

9. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising about 84.2 percent by weight ofdihydrated perchloric acid, about 10.5% by weight of nitric acid andabout 5.3 percent by weight of water and a fuel selected from the groupconsisting of light metals, metal hydrides, and mixtures thereof.

10. In a rocket propellant system a liquid oxidizer consistingessentially of from about 59 percent to about 77 percent by weight ofperchloric acid, from 0 to about 15 percent by weight of HNO and theremainder water, the amount of water being sufficient to form dihydratedperchloric acid with at least about percent of the perchloric acid.

11. In a rocket propellant system a liquid oxidizer consistingessentially of about 90 percent by weight dihydrated perchloric acid,about 8 percent by weight nitric acid and about 2 percent by weightwater.

12. In a rocket propellant system a liquid oxidizer consistingessentially of about 93 percent by weight dihydrated perchloric acid,about 6 percent by weight nitric acid and about 1 percent by weightwater.

13. In a rocket propellant system a liquid oxidizer consistingessentially of about 84.2 percent by weight dihydrated perchloric acid,about 10.5 percent by weight nitric acid, and about 5.3 percent byweight water.

1. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising substantially dihydrated perchloric acidand a fuel selected from the group consisting of light metals, metalhydrides and mixtures thereof.
 2. A method of producing thrust whichcomprises reacting in a combustion chamber an oxidizer comprisingsubstantially dihydrated perchloric acid and a fuel consistingpredominantly of a light metal.
 3. A method of producing thrust whichcomprises reacting in a combustion chamber an oxidizer comprisingsubstantially dihydrated perchloric acid and a fuel consistingpredominantly of a metal hydride.
 4. A method of producing thrust whichcomprises reacting in a combustion chamber an oxidizer comprisingsubstantially dihydrated perchloric acid and a fuel consistingpredominantly of Zr.
 5. A method of producing thrust which comprisesreacting in a combustion chamber an oxidizer comprising substantiallydihydrated perchloric acid and a fuel consisting predominantly of ZrH2.6. A method of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising substantially dihydrated perchloric acidand a fuel consisting predominantly of AlH3.
 7. A METHOD OF PRODUCINGTHRUST WHICH COMPRISES REACTING IN A COMBUSTION CHAMBER AN OXIDIZERCOMPRISING A LIQUID COMPOSITION CONSITING ESSENTIALLY OF FROM ABOUT 59PERCENT TO ABOUT 77 PERCENT BY WEIGHT OF PERCHLORIC ACID, FROM 0 TOABOUT 15 PERCENT BY WEIGHT OF HNO3 AND THE REMAINDER WATER, THE AMOUNTOF WATER BEING SUFFICIENT TO FORM DIHYDRATED PERCHLORIC ACID WITH ATLEAST ABOUT 95 PERCENT OF THE PERCHLORIC ACID AND A FUEL SELECTED FROMTHE GROUP CONSISTING OF LIGHT METALS. METAL HYDRIDES, AND MIXTUESTHEREOF.
 8. A method of producing thrust which comprises reacting in acombustion chamber an oxidizer comprising about 90 percent by weight ofdihydrated perchloric acid, about 8 percent by weight of nitric acid andabout 2% by weight of water and a fuel selected from the groupconsisting of light metals, metal hydrides, and mixtures thereof.
 9. Amethod of producing thrust which comprises reacting in a combustionchamber an oxidizer comprising about 84.2 percent by weight ofdihydrated perchloric acid, about 10.5% by weight of nitric acid andabout 5.3 percent by weight of water and a fuel selected from the groupconsisting of light metals, metal hydrides, and mixtures thereof.
 10. Ina rocket propellant system a liquid oxidizer consisting essentially offrom about 59 percent to about 77 percent by weight of perchloric acid,from 0 to about 15 percent by weight of HNO3 and the remainder water,the amount of water being sufficient to form dihydrated perchloric acidwith at least about 95 percent of the perchloric acid.
 11. In a rocketpropellant system a liquid oxidizer consisting essentially of about 90percent by weight dihydrated perchloric acid, about 8 percent by weightnitric acid and about 2 percent by weight water.
 12. In a rocketpropellant system a liquid oxidizer consisting essentially of about 93percent by weight dihydrated perchloric acid, about 6 percent by weightnitric acid and about 1 percent by weight water.
 13. In a rocketpropellant system a liquid oxidizer consisting essentially of about 84.2percent by weight dihydrated perchloric acid, about 10.5 percent byweight nitric acid, and about 5.3 percent by weight water.